NEW DELHI -- A court with the top investigating agency in India sentenced three of the six conspirators in a 1999 airline hijacking to life in prison.

A court with the Indian Central Bureau of Investigation charged three hijackers under the country's anti-hijacking law and for attempted abduction, conspiracy and murder, India's NDTV reported Tuesday.

The report said the three masterminds behind the hijacking escaped prosecution. Officials let those three escape in exchange for hostages during the 1999 negotiations in the hijacking of an Indian Airlines plan bound for Kandahar.

Survivors of the event said the trial is meaningless without prosecuting the ringleaders, NDTV reported.

Indian intelligence officials said they believe one of the escaped principal hijackers, Ibrahim Athar, is a current key figure in the Jaish-e-Mohammed, which is designated a foreign terror organization by the U.S. State Department.